DESIGN STUDY FOR THE ENVIRONMENTAL UPGRADE OF DENDROPOTAMOS RIVER (PHASES A AND B)

Client: Planning and Environmental Protection AgencyYear: 1998

ISSUEThe purpose of the study was the design of the required works for the environmental upgrade of Dendropotamos River which traverses the Municipalities of Stavroupoli, Polixni, Neapoli, Sikeon, Agios Pavlos, Abelokipoi, Evosmos, Menemenis, Eleftheriou, Kordeliou, Oraiokastro and Nea Ionia and the communities of Nea Efkarpia, Filiros, Asvestoxori, Exohi and Pefkes.

SOLUTIONThe study included 3 phases:View of Dendropotamos River from Municipality of Polixni• Phase A, which included the recording and evaluation of the existing the environmental impacts and hazards in the study area. Moreover, a reference to the existing natural and human environment was made and a description and analysis of the overall environmental profile of biotic, abiotic and socioeconomic data in the study area was presented. Finally, important environmental and social issues along with their causes were presented.• Phase B, which included the ranking of the proposals for the required studies and works for flood protection, decontamination, remediation and restoration of the riverbed and landscaping works for walking and recreation. • Phase C, which included the final study for “Hydraulic Arrangement works of Dendropotamos River from Konstantinoupoleos bridge to the internal regional road”. The study area consists of the mountainous and plain part of the drainage basin of Dendropotamos River from the mountainous area to the river discharge into the sea, including all the tributaries which are the torrents of Diabaton, Ilioupoleos, Asimaki, Xiropotamos, Anonimos, and Oraiokastro.

The study area is crossed by Dendropotamos River and from other tributaries which flow into the south part of the main branch of Dendropotamos which discharges into the Thermaikos Gulf. The region is environmentally deteriorated due to industrial, commercial and animal farming facilities etc. many of which pollute the Dendropotamos River. Moreover, there is a lack of infrastructure in some of the aforementioned communities and municipalities, mostly due to illegal construction in the western urban area of Thessaloniki which hinders the work of the public authorities. In addition, there is lack of appropriate infrastructure for sewerage and water supply.

The existing condition of the Dendropotamos river bed, indicates that flooding is the most important issue of the drainage basin of Dendropotamos River.

The purpose of the intervention works is flood protection and aesthetic environmental upgrade of Dendropotamos zone within Polixni region from Konstantinoupoleos street to the internal regional roadway (LTOTAL=551m). The existing river cross section will be preserved, which with appropriate arrangement (installation of gabions and vegetation on slopes), can upgrade and secure environmentally and hydraulically the river. The critical flow discharge is Q=130m3/s for a rainfall with recurrence interval of T=100 years.

The open rectangular cross section of the river bed has a width of 6m, slope gradient 1, 5 (3:2) and maximum flow depth yMAX=2,41m.

The longitudinal slope gradient is S=0.019 or 19% and according to aforementioned dimensions, the fluid cross section area is 23,06m2.

Along the river bed a sewerage network is installed with 600mm diameter pipes and manholes every 50m. Finally, reinforced safety zones from concrete are constructed every 50m, across the river width.

BENEFIT

The design study contributed to the environmental upgrade of Dendropotamos River.